Photoacid generators and photoresists comprising same

ABSTRACT

This invention relates to new photoacid generator compounds and photoresist compositions that comprise such compounds. In particular, the invention relates to photoacid generator compounds that generate an anthracene acid upon exposure to activating radiation, particularly anthracene sulfonic acids such as acids that include 9,10-dialkoxyanthracene-2-sulfonate moieties. Positive- and negative-acting chemically amplified resists that contain such PAGs and that are imaged with I-line (365 nm) radiation are particularly preferred.

[0001] The present application claims the benefit of U.S. provisionalapplication No. 60/096,648, filed Aug. 14, 1998, which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to new photoacid generator compounds(“PAGs”) and photoresist compositions that comprise such compounds. Inparticular, the invention relates to photoacid generator compounds thatgenerate an anthracene acid upon exposure to activating radiation,particularly anthracene sulfonate acids such as acids that include9,10-dialkoxyanthracene-2-sulfonate moieties. Positive- andnegative-acting chemically amplified resists that contain such PAGs andthat are imaged with I-line (365 nm) radiation are particularlypreferred.

[0004] 2. Background

[0005] Photoresists are photosensitive films for transfer of images to asubstrate. They form negative or positive images. After coating aphotoresist on a substrate, the coating is exposed through a patternedphotomask to a source of activating energy such as ultraviolet light toform a latent image in the photoresist coating. The photomask has areasopaque and transparent to activating radiation that define an imagedesired to be transferred to the underlying substrate. A relief image isprovided by development of the latent image pattern in the resistcoating. The use of photoresists is generally described, for example, byDeforest, Photoresist Materials and Processes, McGraw Hill Book Company,New York (1975), and by Moreau, Semiconductor Lithography, Principals,Practices and Materials, Plenum Press, New York (1988).

[0006] Known photoresists can provide features having resolution andsize sufficient for many existing commercial applications. However formany other applications, the need exists for new photoresists that canprovide highly resolved images of submicron dimension.

[0007] Various attempts have been made to alter the make-up ofphotoresist compositions to improve performance of functionalproperties. Among other things, a variety of photoactive compounds havebeen reported for use in photoresist compositions. See, e.g., U.S. Pat.No. 4,450,360 and European Application 615163.

[0008] More recently, certain “chemically amplified” photoresistcompositions have been reported. Such photoresists may benegative-acting or positive-acting and rely on multiple crosslinkingevents (in the case of a negative-acting resist) or deprotectionreactions (in the case of a positive-acting resist) per unit ofphotogenerated acid. In other words, the photogenerated acid actscatalytically. In the case of positive chemically amplified resists,certain cationic photoinitiators have been used to induce cleavage ofcertain “blocking” groups pendant from a photoresist binder, or cleavageof certain groups that comprise a photoresist binder backbone. See, forexample, U.S. Pat. Nos. 5,075,199; 4,968,851; 4,883,740; 4,810,613; and4,491,628, and Canadian Patent Application 2,001,384. Upon selectivecleavage of the blocking group through exposure of a coating layer ofsuch a resist, a polar functional group is provided, e.g., carboxyl,phenol or imide, which results in different solubility characteristicsin exposed and unexposed areas of the resist coating layer.

SUMMARY OF THE INVENTION

[0009] I have now discovered novel photoacid generator compounds (PAGs)for use in either positive-acting or negative-acting photoresistcompositions.

[0010] In particular, the invention provides photoacid generators thatcan produce an optionally substituted anthracene sulfonic acid uponexposure to activating radiation, particularly an alkoxy anthracenesulfonic acid such as 9,10-dialkoxyanthracene-2-sulfonic acid;anthracene disulfonic acid such as9,10-dialkoxyanthracene-2,6-disulfonic acid and9,10-dialkoxyanthracene-2,5-disulfonic acid; and anthracene acids thathave both sulfonic acid and alkanoyl (e.g. —COOR where R is optionallysubstituted C₁₋₁₂ alkyl, preferably C₁₋₆ alkyl) moieties such as9,10-dialkoxyanthracene-2-sulfonic acid-7-methylester and the like.

[0011] Preferably, PAGs of the invention are used in positive-acting ornegative-acting chemically amplified photoresists, i.e. negative-actingresist compositions which undergo a photoacid-promoted crosslinkingreaction to render exposed regions of a coating layer of the resist lessdeveloper soluble than unexposed regions, and positive-acting resistcompositions which undergo a photoacid-promoted deprotection reaction ofacid labile groups of one or more composition components to renderexposed regions of a coating layer of the resist more soluble in anaqueous developer than unexposed regions. A preferred imaging wavelengthis I-line (365 nm), although other exposure wavelengths also can beutilized, including shorter wavelengths such as sub-300 nm wavelengthse.g. 248 nm. Longer wavelengths such as G-line (435 nm) also can beemployed, particularly where a sensitizer is employed as an additionalresist component.

[0012] The invention also provide methods for forming relief images ofthe photoresists of the invention, including methods for forming highlyresolved patterned photoresist images (e.g. a patterned line havingessentially vertical sidewalls) of sub-micron and even sub-half orsub-quarter micron dimensions.

[0013] The invention further provides articles of manufacture comprisingsubstrates such as a microelectronic wafer or a flat panel displaysubstrate having coated thereon the photoresists and relief images ofthe invention. Other aspects of the invention are disclosed infra.

DETAILED DESCRIPTION OF THE INVENTION

[0014] In a first aspect of the invention, iodonium PAGs are providedthat can generate an anthracene sulfonic acid, such as diaryliodoniumsalts that have a counter anion of an anthracene sulfonate. Generallypreferred are optionally substituted diphenyliodoium salts that havesuch an anthracene sulfonate counter anion, such as PAGs of thefollowing Formula I:

[0015] wherein R¹ and R² are each independently a non-hydrogensubstituent such as halo; hydroxy; nitro; cyano; sulfonyl; optionallysubstituted alkyl preferably having from 1 to about 20 carbon atoms,more preferably 1 to about 8 carbon atoms; optionally substituted alkoxypreferably having from 1 to about 20 carbon atoms, more preferably 1 toabout 8 carbon atoms; optionally substituted aminoalkyl preferablyhaving from 1 to about 20 carbon atoms, more preferably 1 to about 8carbon atoms; optionally substituted alkylthio preferably having from 1to about 20 carbon atoms, more preferably 1 to about 8 carbon atoms;optionally substituted alkylsulfinyl preferably having from 1 to about20 carbon atoms, more preferably 1 to about 8 carbon atoms; optionallysubstituted alkylsulfonyl preferably having from 1 to about 20 carbonatoms, more preferably 1 to about 8 carbon atoms; optionally substitutedaryloxy such as phenoxy; optionally substituted aralkyl such as benzyl;optionally substituted alkanoyl preferably having from 1 to about 20carbons atoms with acetyl being a preferred group; optionallysubstituted carbocyclic aryl such as phenyl, naphthyl, biphenyl, and thelike; optionally substituted heteroaromatic or heteroalicyclic having 1to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 heteroatoms such as coumarinyl, quinolinyl, pyridyl, pyrazinyl, pyrimidyl,furyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, indolyl,benzofuranyl, benzothiazol, tetrahydrofuranyl, tetrahydropyranyl,piperdinyl, morpholino, pyrrolindinyl, etc.; and the like;

[0016] R³ and R⁴ are the same or different and are selected from thesame group as defined for R¹ and R² above, and preferably R³ and R⁴ arealkoxy such as preferably C₁₋₁₂ alkoxy, more preferably C₁₋₆ alkoxy suchas methoxy, ethoxy, propoxy, etc., and preferably R³ and R⁴ aresubstituted at the 9 and 10 position of the anthracene ring,respectively;

[0017] preferably the SO₃ ⁻ group is substituted at the 2-position ofthe anthracene ring;

[0018] m and n are each independently an integer of from 0 (where therespective phenyl is fully hydrogen-substituted) to 5, and preferably mand n are each 0, 1, or 2; and

[0019] o and p are each independently an integer of 0 or greater,wherein the sum of o and p is 9 or less, and preferably o and p are each1.

[0020] Also preferred are optionally substituted dinaphthyliodoniumsalts that have such an anthracene sulfonate counter anion, such as PAGsof the following Formula II:

[0021] wherein R¹, R², R³, R⁴, o and p are each as defined above forFormula I, and preferably R³ and R⁴ are alkoxy such as C₁₋₁₂ alkoxy morepreferably C₁₋₆ alkoxy, with the R³ and R⁴ moieties preferablysubstituted at the 9 and 10 position of the anthracene ring,respectively, and preferably the SO₃ ⁻ group is substituted at the2-position of the anthracene ring; and

[0022] m and n are each independently an integer from 0 (where therespective phenyl is fully hydrogen-substituted) to 7, and preferably mand n are each 1, 2 or 3.

[0023] Such iodonium salts can be prepared by known procedures. See, forexample, U.S. Pat. Nos. 4,442,197; 4,603,101; and 4,624,912; andEuropean Application 0708368A1.

[0024] In another aspect of the invention, optionally substitutedN-oxyimidosulfonate PAGs are provided that have an anthracene moiety.Preferred are optionally substituted N-oxyimidosulfonate PAGs that havea dialkoxy anthracene moiety, preferably a 9,10-dialkoxy anthracenesubstituted at the 2-position with a sulfonate group, such as PAGs ofthe following Formula III:

[0025] wherein R³, R⁴, o and p are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₁₂ alkoxy, morepreferably C₁₋₆ alkoxy, preferably substituted at the 9 and 10 positionof the anthracene ring, respectively, and preferably the —SO₃— group issubstituted at the 2-position of the anthracene ring; and

[0026] R⁵ and R⁶ are independently optionally substituted alkylpreferably having 1 to about 10 carbon atoms; optionally substitutedalkoxy preferably having 1 to about 10 carbon atoms; or optionallysubstituted alkylthio preferably having 1 to about 10 carbon atoms,

[0027] or more preferably R⁵ and R⁶ are taken together to form anoptionally substituted alkylene or alkenylene chain preferably having2-5 carbons so as to ring with the N and C═O groups. Such compounds canbe readily prepared from open chain and cyclic N-hydroxyimides, e.g.N-hydroxy-succinimide, N-hydroxymaleimide, N-hydroxyphthalimide,N-hydroxy-1,8-naphthalimide, N-hydroxy-5-norbornene-2,3-dicarboximide,OHN((C═O)CH₃)₂ and the like. See also International ApplicationWO94/10608 for preparation of N-sulfonyloxyimide PAGs.

[0028] In yet a further aspect of the invention, optionally substitutedN-oxyimino sulfonate PAGs are provided that have an anthracene moiety.Preferred are optionally substituted N-oxyiminosulfonate PAGs that havea dialkoxy anthracene moiety, preferably a 9,10-dialkoxy anthracenesubstituted at the 2-position with a sulfonate group, such as PAGs ofthe following Formula IV:

[0029] wherein R³, R⁴, o and p are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₆ alkoxy, morepreferably substituted at the 9 and 10 position of the anthracene ring,respectively, and preferably the —SO₃— group is substituted at the2-position of the anthracene ring; and

[0030] R⁵ and R⁶ are the same as defined in Formula III above. Suchcompounds can be readily prepared from oximes of open chain and cyclicketones such as cyclohexanone, α-tetralone, pentanone, etc.

[0031] One preferred group of N-oxyiminosulfonate PAGs are α-cyanocompounds, such as those of the following Formula V:

[0032] wherein R³, R⁴, o and p are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₆ alkoxy, morepreferably substituted at the 9 and 10 position of the anthracene ring,respectively, and preferably the —SO₃— group is substituted at the2-position of the anthracene ring; and

[0033] R⁷ is optionally substituted alkyl (including cyclic alkyl),preferably having 1 to about 10 carbon atoms; optionally substitutedcarbocyclic aryl such as phenyl and the like, particularly alkoxyphenylsuch as methoxy. Such compounds can be prepared from open chain andcyclic acetonitrile derivatives such as 4-methoxybenzeneaectonitrile(CH₃OC₆H₄CH₂CN) and 1-cyclohexenylacetonitrile.

[0034] In a further aspect of the invention, optionally substitutedphenolic sulfonate PAGs are provided that have one or more anthracenemoieties. Such compounds have anthracenyl sulfonate groups grafted ontoone or more phenolic —OH moieties, preferably two or three anthracenylsulfonate groups on a single phenyl group. Preferred phenolic sulfonatecompounds include PAGs of the following Formula VI:

[0035] wherein R¹, R³, R⁴, p and o are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₆ alkoxy, morepreferably substituted at the 9 and 10 position of the anthracene ring,respectively, and preferably the —SO₃— group is substituted at the2-position of the anthracene ring;

[0036] m is an integer from 0 to 4;

[0037] z is an integer from 1 to 6, and z is preferably is 1, 2, 3 or 4,and the sum of m and z does not exceed 6.

[0038] Preferred compounds of Formula VI include those where z is 3,particularly where the phenyl ring is substituted by anthracenylsulfonate at the 1, 2, 3-positions (i.e. pyrogallol-based compounds), or1, 3, 5-positions (i.e. phloroglucinol-based compounds), such ascompounds of the following structures (A) and (B):

[0039] wherein each Y group of those compounds (A) and (B) isindependently a group of the formula:

[0040] Compounds of Formula VI can be readily prepared, e.g. by reactionof a phenolic compound with an anthracenyl sulfonate reagent (e.g.anthracene sulfonyl chloride) to thereby transfer the desired anthracenemoieties onto the phenolic base compound.

[0041] Optionally substituted benzylic sulfonate PAGs are provided thathave one or more anthracene moieties. Such compounds have anthracenylsulfonate groups grafted onto one or more benzylic carbons, preferablyone or two anthracenyl sulfonate groups on a single phenyl base group.Preferred benzylic sulfonate compounds include PAGs of the followingFormula VII:

[0042] wherein R¹, R³, R⁴, p and o are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₁₂ alkoxy, morepreferably C₁₋₆ alkoxy, preferably substituted at the 9 and 10 positionof the anthracene ring, respectively, and preferably the SO₃ ⁻ group issubstituted at the 2-position of the anthracene ring; and

[0043] m is an integer from 0 to 4;

[0044] z is an integer from 1 to 6, and z is preferably is 1, 2 or 3,and the sum of m and z does not exceed 6.

[0045] Preferred compounds of Formula VII include those where z is 1 or2, and the phenyl ring is substituted by one or more nitro, haloparticularly fluoro, alkyl particularly C₁₋₆ alkyl, or alkoxyparticularly C₁₋₆ alkoxy, such as compounds of the following structures(A) and (B):

[0046] wherein each Y group of those compounds (A) and (B) isindependently a group of the formula

[0047] Compounds of Formula VII can be prepared, e.g., by reaction of abenzylic alcohol compound with an anthracenyl sulfonate reagent (e.g.anthracene sulfonyl chloride) to thereby transfer the desired anthracenemoieties onto the benzylic base compound. See also the proceduresreported in EPO Application EP 0717319A1 and U.S. Pat. No. 5,344,742 toSinta et al.

[0048] The invention also provides anthracenyl disulfone PAGs, such ascompounds of the following Formula VIII:

[0049] wherein each R³, R⁴, p and o are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₁₂ alkoxy,preferably C₁₋₆ alkoxy, preferably substituted at the 9 and 10 positionof the anthracene ring, respectively, and preferably the SO₃ ⁻ group issubstituted at the 2-position of the anthracene ring.

[0050] Generally preferred are 9,10-alkoxy 2-sulfonate anthracenecompounds such as PAGs of the following structures:

[0051] The invention also provides anthracenyl diazosulfone PAGs, suchas compounds of the following Formula IX:

[0052] wherein each R³, R⁴, p and o are the same or different and arethe same as defined in Formula I above, and preferably each R³ and R⁴are alkoxy such as C₁₋₁₂ alkoxy, preferably C₁₋₆ alkoxy, preferablysubstituted at the 9 and 10 position of the respective anthracene ring,and preferably each SO₃ ^(− group is substituted at the) 2-position ofthe respective anthracene ring.

[0053] Generally preferred are 9,10-alkoxy 2-sulfonate compounds such asPAGs of the following structures:

[0054] Such disulfone and diazosulfone PAGs of the invention can besynthesized by generally known procedures. See, for example, EuropeanApplication 0708368A1 and U.S. Pat. No. 5,558,976.

[0055] The invention further provides PAGs that are sulfonium salts ofanthracene sulfonates. Preferred compounds include triarylsulfoniumsalts, particularly triphenylsulfonium groups that have an optionallysubstituted anthracene sulfonate counter anion. Generally preferred aresulfonium salts of the following Formula X:

[0056] wherein R³, R⁴, p and o are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₁₂ alkoxy,preferably C₁₋₆ alkoxy, preferably substituted at the 9 and 10 positionof the anthracene ring, respectively, and preferably the SO₃ ⁻ group issubstituted at the 2-position of the anthracene ring;

[0057] R⁸, R⁹, R¹⁰ are each independently selected from the same groupas defined for R¹ and R² in Formula I above;

[0058] r, s, t are independently integers from 0 (where the phenyl ringis fully hydrogen-substituted) to 5.

[0059] Also preferred are aryl(dialkyl)sulfonium anthracene sulfonatesalts, particularly phenyl(dialkyl)sulfonium, naphthyl(dialkyl)sulfoniumand acenaphthyl(dialkyl)sulfonium groups that have an optionallysubstituted anthracene sulfonate counter anion, such asphenyl(dialkyl)sulfonium compounds of the following Formula XI:

[0060] wherein R³, R⁴, p and o are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₆ alkoxy, morepreferably substituted at the 9 and 10 position of the anthracene ring,respectively, and preferably the SO₃ ⁻ group is substituted at the2-position of the anthracene ring; and

[0061] R⁸ and r are the same as defined in Formula X above;

[0062] each Alk is the same or different optionally substituted alkyl,preferably having from 1 to about 20 carbon atoms, more preferably 1 toabout 12 carbon atoms, still more preferably 1 to about 6 carbon atoms,

[0063] or each Alk may be taken together and form a C2-8 alkylene oralkenylene chain and thereby form a ring with the sulfur cation,preferably having from 5 to about 9 total ring members (inclusive of thesulfur), more preferably 5 to about 7 ring members.

[0064] Also preferred are naphthyl(dialkyl)sulfonium compounds ofFormula XIA and acenaphthyl(dialkyl)sulfonium compounds of Formula XIB,which Formulae XIA and XIB are defined the same as Formula XI above,except that in Formula XIA the sulfonium component is(R⁸)r-(naphthyl)-S-(Alk)₂ with r being an integer from 0 to 7; and thatin Formula XIB the sulfonium component is (R⁸)r-(acenaphthyl)-S-(Alk)₂with r being an integer from 0 to 9.

[0065] The invention further provides PAGs that are phenacylsulfoniumsalts of optionally substituted anthracene sulfonates, such as compoundsof the following Formula XII:

[0066] wherein R³, R⁴, p and o are the same as defined in Formula Iabove, and preferably R³ and R⁴ are alkoxy such as C₁₋₆ alkoxy, morepreferably substituted at the 9 and 10 position of the anthracene ring,respectively, and preferably the SO₃ ⁻ group is substituted at the2-position of the anthracene ring;

[0067] R⁸ and r are the same as defined in Formula X above;

[0068] each Alk is the same or different optionally substituted alkyl,preferably having from 1 to about 20 carbon atoms, more preferably 1 toabout 12 carbon atoms, still more preferably 1 to about 6 carbon atoms,

[0069] or each Alk may be taken together and form a C2-8 alkylene oralkenylene chain and thereby form a ring with the sulfur cation,preferably having from 5 to about 9 total ring members (inclusive of thesulfur), more preferably 5 to about 7 ring members.

[0070] Also preferred are naphthylacylsulfonium compounds of FormulaXIIA and acenaphthyl(acyl)sulfonium compounds of Formula XIIB, whichFormulae XIIA and XIB are defined the same as Formula XII above, exceptthat in Formula XIIA the sulfonium component is(R⁸)r-(naphthyl)CH₂C(═O)—S-(Alk)₂ with r being an integer from 0 to 7;and that in Formula XIIB the sulfonium component is(R⁸)r-(acenaphthyl)-CH₂C(═O)—S-(Alk)₂ with r being an integer from 0 to9.

[0071] Sulfonium salt PAGs of the invention can be prepared by knownprocedures, including those methods disclosed in U.S. Pat. No. 5,371,364to Sinta et al.

[0072] Additional preferred photoacid generators of the inventioninclude PAGs that correspond to the above Formula I, II, III, IV, V, VI,VII, VIII, IX, X, XI, XIA, XIB, XIIA and XIIB, but that generate uponexposure to activating radiation an anthracene disulfonic acid,preferably a dialkoxyanthracene disulfonic acid, preferably where thealkoxy groups are C₁₋₁₂ alkoxy or C₁₋₆ alkoxy, more preferably presentat 9 and 10 ring positions of the anthracene ring and the disulfonicacid groups present at the 2 and 6 ring positions or the 2 and 5anthracene ring positions. For example, preferred acids include9,10-dialkoxyanthracene-2,6-disulfonic acid and9,10-dialkoxyanthracene-2,5-disulfonic acid, optionally substituted suchas by the same groups specified for R³ and R⁴ above, with suchsubstituents limited of course by available valences of the anthraceneacid. These preferred compounds include PAGs of Formulae I′, II′, III′,IV′, V′, VI′, VII′, VIII′, IX′, X′, XI′, XIA′, XIB′, XIIA′ and XIIB′,which formulae are defined the same as Formulae I, II, III, IV, V, VI,VII, VIII, IX, X,XI, XIA, XIB, XIIA and XIIB respectively, except theanthracene group has an additional —SO₃ moiety, and the sum of p and ois 8 or less.

[0073] Still further preferred photoacid generators of the inventioninclude PAGs that correspond to the above Formula I, II, III, IV, V, VI,VII, VIII, IX, X, XI, XIA, XIB, XIIA and XIIB, but that generate uponexposure to activating radiation an anthracene acid that has bothsulfonic acid and alkanoyl (i.e. an ester ring group such as e.g. —COORwhere R is optionally substituted C₁₋₁₂ alkyl such as methyl, ethyl,propyl, etc.) moieties, preferably a dialkoxyanthracne alkanyol/sulfonicacid, preferably where the alkoxy groups are C₁₋₁₂ alkoxy or C₁₋₆alkoxy, more preferably present at 9 and 10 ring positions of theanthracene ring and the alkanoyl sulfonic acid groups present at the 2and 6 ring positions, the 2 and 5 anthracene ring positions, or the 2and 7 anthracene ring positions. For example, preferred such acidsinclude 9,10-dialkoxyanthracene-2-sulfonic acid-7-methylester,optionally substituted such as by the same groups specified for R³ andR⁴ above, with such substituents limited of course by available valencesof the anthracene acid. These preferred compounds include PAGs ofFormulae I″, II″, III″, IV″, V″, VI″, VII″, VIII″, IX″, X″, XI″, XIA″,XIB″, XIIA″ and XIIB″, which formulae are defined the same as FormulaeI, II, III, IV, V, VI, VII, VIII, IX, X, XI, XIA, XIB, XIIA and XIIBrespectively, except the anthracene group has an additional alkanoylmoiety, and the sum of p and o is 8 or less.

[0074] As mentioned above, various substituent groups of PAGs of theinvention may be optionally substituted. Substituted moieties (includingsubstituted R¹ through R¹⁰ Alk, anthracene groups, etc) are suitablysubstituted at one or more available positions by, e.g., halogen such asF, Cl Br and/or I, alkyl including C₁₋₁₆ alkyl with C₁₋₈ alkyl beingpreferred, alkoxy including C₁₋₁₆ alkoxy having one or more oxygenlinkages with C₁₋₈ alkoxy being preferred, alkenyl including C₂₋₁₂alkenyl with C₂₋₈ alkenyl being preferred, alkenyl including C₂₋₁₂alkenyl with C₂₋₈ alkynyl being preferred, aryl such as phenyl ornaphthyl and substituted aryl such as halo, alkoxy, alkenyl, alkynyland/or alkyl substituted aryl, preferably having the number of carbonatoms mentioned above for corresponding groups. Preferred substitutedaryl groups include substituted phenyl, anthracenyl and naphthyl.

[0075] As used herein, the term alkyl unless otherwise modified refersto both cyclic and noncyclic groups, although of course cyclic groupswill comprise at least three carbon ring members. Aryl groups, such asthose of triarylsulfonium PAGs, are preferably carbocyclic aryl e.g.phenyl, naphthyl, etc., rather than heteroaromatic groups.

[0076] As discussed above, PAGs of the invention are useful as theradiation sensitive component in photoresist compositions, includingboth positive-acting and negative-acting chemically amplified resistcompositions.

[0077] The photoresists of the invention typically comprise a resinbinder and a photoactive component of the invention as described above.Preferably the resin binder has functional groups that impart alkalineaqueous developability to the resist composition. For example, preferredare resin binders that comprise polar functional groups such as hydroxylor carboxylate. Preferably the resin binder is used in a resistcomposition in an amount sufficient to render the resist developablewith an aqueous alkaline solution. For example, preferred resin bindersare phenolic resins including phenol aldehyde condensates known in theart as novolak resins, homo and copolymers of alkenyl phenols and homoand copolymers of N-hydroxyphenyl-maleimides.

[0078] Examples of suitable phenols for condensation with a aldehyde,especially formaldehyde, for the formation of novolak resins includephenol; m-cresol; o-cresol; p-cresol; 2,4-xylenol; 2,5-xylenol;3,4-xylenol; 3,5-xylenol; thymol and mixtures thereof. An acid catalyzedcondensation reaction results in formation of a suitable novolak resinwhich may vary in molecular weight from about 500 to 100,000 daltons.Poly(vinylphenols) may be prepared, e.g., as disclosed in U.S. Pat. No.4,439,516. Preferred resin binders and the preparation thereof are alsodisclosed in U.S. Pat. No. 5,128,230.

[0079] Poly(vinylphenols) may be formed by block polymerization,emulsion polymerization or solution polymerization of the correspondingmonomers in the presence of a catalyst. Vinylphenols useful for theproduction of polyvinyl phenol resins may be prepared, for example, byhydrolysis of commercially available coumarin or substituted coumarin,followed by decarboxylation of the resulting hydroxy cinnamic acids.Useful vinylphenols may also be prepared by dehydration of thecorresponding hydroxy alkyl phenols or by decarboxylation of hydroxycinnamic acids resulting from the reaction of substituted ornonsubstituted hydroxybenzaldehydes with malonic acid. Preferredpolyvinylphenol resins prepared from such vinylphenols have a molecularweight range of from about 2,000 to about 60,000 daltons.

[0080] Copolymers containing phenol and nonaromatic cyclic alcohol unitsalso are preferred resin binders for resists of the invention and may besuitably prepared by partial hydrogenation of a novolak orpoly(vinylphenol) resin. Such copolymers and the use thereof inphotoresist compositions are disclosed in U.S. Pat. No. 5,128,232 toThackeray et al.

[0081] Further preferred resin binders include resins formed frombishydroxymethylated compounds, and block novolak resins. See U.S. Pat.Nos. 5,130,410 and 5,128,230 where such resins and use of same inphotoresist compositions is disclosed. Additionally, two or more resinbinders of similar or different compositions can be blended or combinedtogether to give additive control of lithographic properties of aphotoresist composition. For instance, blends of resins can be used toadjust photospeed and thermal properties and to control dissolutionbehavior of a resist in a developer.

[0082] Preferably, a photoacid generator compound of the invention isemployed in a chemically amplified positive-acting resist. A number ofsuch resist compositions have been described, e.g., in U.S. Pat. Nos.4,968,581; 4,883,740; 4,810,613 and 4,491,628 and Canadian PatentApplication 2,001,384, all of which are incorporated herein by referencefor their teaching of making and using chemically amplifiedpositive-acting resists. In accordance with the present invention, thoseprior resist compositions are modified by substitution of thephotoactive component of the invention as the radiation sensitivecomponent.

[0083] A particularly preferred chemically amplified photoresist of theinvention comprises in admixture a photoactive component of theinvention and a resin binder that comprises a copolymer containing bothphenolic and non-phenolic units. For example, one preferred group ofsuch copolymers has acid labile groups substantially, essentially orcompletely only on non-phenolic units of the copolymer. One especiallypreferred copolymer binder has repeating units x and y of the followingformula:

[0084] wherein the hydroxyl group be present at either the ortho, metaor para positions throughout the copolymer, and R′ is substituted orunsubstituted alkyl having 1 to about 18 carbon atoms, more typically 1to about 6 to 8 carbon atoms. Tert-butyl is a generally preferred R′group. An R′ group may be optionally substituted by e.g. one or morehalogen (particularly F, Cl or Br), C₁₋₈ alkoxy, C₂₋₈ alkenyl, etc. Theunits x and y may be regularly alternating in the copolymer, or may berandomly interspersed through the polymer. Such copolymers can bereadily formed. For example, for resins of the above formula, vinylphenols and a substituted or unsubstituted alkyl acrylate such ast-butylacrylate and the like may be condensed under free radicalconditions as known in the art. The substituted ester moiety, i.e.R′—O—C(═O)—, moiety of the acrylate units serves as the acid labilegroups of the resin and will undergo photoacid induced cleavage uponexposure of a coating layer of a photoresist containing the resin.Preferably the copolymer will have a M_(w) of from about 8,000 to about50,000, more preferably about 15,000 to about 30,000 with a molecularweight distribution of about 3 or less, more preferably a molecularweight distribution of about 2 or less. Non-phenolic resins, e.g. acopolymer of an alkyl acrylate such as t-butylacrylate ort-butylmethacrylate and a vinyl alicyclic such as a vinyl norbornyl orvinyl cyclohexanol compound, also may be used as a resin binder incompositions of the invention. Such copolymers also may be prepared bysuch free radical polymerization or other known procedures and suitablywill have a M_(w) of from about 8,000 to about 50,000, and a molecularweight distribution of about 3 or less.

[0085] Another preferred resin binder for a positive chemicallyamplified resist of the invention has phenolic and nonaromatic cyclicalcohol units, wherein at least of portion of the hydroxyl groups of thecopolymer are bonded to acid labile groups. Preferred acid labilemoieties are acetate groups including t-butyl acetate groups of theformula (CH₃)₃COC(O)CH₂—; oxycarbonyl groups such as t-butyl oxycarbonyl(t-Boc) groups of the formula (CH₃)₃CC(O)O—; and acetal and ketals.Chemically amplified positive-acting photoresists containing such acopolymer have been disclosed in U.S. Pat. No. 5,258,257 to Sinta et al.

[0086] Other preferred resins that have acid-labile deblocking groupsfor use in a positive-acting chemically-amplified photoresist of theinvention have been disclosed in European Patent Application 0829766A2of the Shipley Company (resins with acetal and ketal resins) andEuropean Patent Application EP0783 1 36A2 of the Shipley Company(terpolymers and other copolymers includingstyrene/hydroxystyrene/t-butylacrylate copolymers). In general, resinshaving a variety of acid labile groups will be suitable, such as acidsensitive esters, carbonates, ethers, imides, etc. The photoacid labilegroups will more typically be pendant from a polymer backbone, althoughresins that have acid labile groups that are integral to the polymerbackbone also may be employed.

[0087] Preferred negative-acting compositions of the invention comprisea mixture of materials that will cure, crosslink or harden upon exposureto acid, and a photoactive component of the invention.

[0088] Particularly preferred negative acting compositions comprise aresin binder such as a phenolic resin, a crosslinker component and aphotoactive component of the invention. Such compositions and the usethereof has been disclosed in European Patent Applications 0164248 and0232972 and in U.S. Pat. No. 5,128,232 to Thackeray et al. Preferredphenolic resins for use as the resin binder component include novolaksand poly(vinylphenol)s such as those discussed above. Preferredcrosslinkers include amine-based materials, including melamine,glycolurils, benzoguanamine-based materials and urea-based materials.Melamine-formaldehyde resins are generally most preferred. Suchcrosslinkers are commercially available, e.g. the melamine resins soldby American Cyanamid under the trade names Cymel 300, 301 and 303.Glycoluril resins are sold by American Cyanamid under trade names Cymel1170, 1171, 1172, urea-based resins are sold under the trade names ofBeetle 60, 65 and 80, and benzoguanamine resins are sold under the tradenames Cymel 1123 and 1125.

[0089] Photoresists of the invention also may contain other materials.For example, other optional additives include actinic and contrast dyes,anti-striation agents, plasticizers, speed enhancers, sensitizers (e.g.for use of a PAG of the invention at longer wavelenghs such as G-line),etc. Such optional additives typically will be present in minorconcentration in a photoresist composition except for fillers and dyeswhich may be present in relatively large concentrations such as, e.g.,in amounts of from 5 to 30 percent by weight of the total weight of aresist's dry components.

[0090] A preferred optional additive of resists of the invention is anadded base, particularly tetrabutylammonium hydroxide (TBAH), which canenhance resolution of a developed resist relief image. The added base issuitably used in relatively small amounts, e.g. about 1 to 10 percent byweight relative to the PAC, more typically 1 to about 5 weightpercent. 1. Other preferred basic additives include ammonium sulfonatesalts such as piperidinium p-toluenesulfonate and dicyclohexylammoniump-toluenesulfonate; alkyl amines such as tripropylamine anddodecylamine; aryl amines such as diphenylamine, triphenylamine,aminophenol, 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, etc.

[0091] The resin binder component of resists of the invention aretypically used in an amount sufficient to render an exposed coatinglayer of the resist developable such as with an aqueous alkalinesolution. More particularly, a resin binder will suitably comprise 50 toabout 90 weight percent of total solids of the resist. The photoactivecomponent should be present in an amount sufficient to enable generationof a latent image in a coating layer of the resist. More specifically,the photoactive component will suitably be present in an amount of fromabout 1 to 40 weight percent of total solids of a resist. Typically,lesser amounts of the photoactive component will be suitable forchemically amplified resists.

[0092] The photoresists of the invention are generally preparedfollowing known procedures with the exception that a PAG of theinvention is substituted for prior photoactive compounds used in theformulation of such photoresists. For example, a resist of the inventioncan be prepared as a coating composition by dissolving the components ofthe photoresist in a suitable solvent such as, e.g., a glycol ether suchas 2-methoxyethyl ether (diglyme), ethylene glycol monomethyl ether,propylene glycol monomethyl ether; lactates such as ethyl lactate ormethyl lactate, with ethyl lactate being preferred; proponiates,particularly methyl propionate and ethyl propionate; a Cellosolve estersuch as methyl Cellosolve acetate; an aromatic hydrocarbon such tolueneor xylene; or a ketone such as methylethyl ketone, cyclohexanone and2-heptanone. Typically the solids content of the photoresist variesbetween 5 and 35 percent by weight of the total weight of thephotoresist composition.

[0093] The photoresists of the invention can be used in accordance withknown procedures. Though the photoresists of the invention may beapplied as a dry film, they are preferably applied on a substrate as aliquid coating composition, dried by heating to remove solventpreferably until the coating layer is tack free, exposed through aphotomask to activating radiation, optionally post-exposure baked tocreate or enhance solubility differences between exposed and nonexposedregions of the resist coating layer, and then developed preferably withan aqueous alkaline developer to form a relief image.

[0094] The substrate on which a resist of the invention is applied andprocessed suitably can be any substrate used in processes involvingphotoresists such as a microelectronic wafer. For example, the substratecan be a silicon, silicon dioxide or aluminum-aluminum oxidemicroelectronic wafer. Gallium arsenide, ceramic, quartz or coppersubstrates may also be employed. Printed circuit board substrates suchas copper clad laminates are also particularly preferred. Thephotoresists of the invention will be particularly useful for circuitboard imaging, including through hole and other aperture plating.Typical printed circuit board substrates have one or more copper layersinterleaved with resin layers, such as epoxy layers.

[0095] Substrates used for liquid crystal display and other flat paneldisplay applications are also suitably employed, e.g. glass substrates,indium tin oxide coated substrates and the like.

[0096] A liquid coating resist composition may be applied by anystandard means such as spinning, dipping or roller coating. Photoresistsof the invention also may be formulated and applied as dry film resists,particularly for printed circuit board manufacture applications. Theexposure energy should be sufficient to effectively activate thephotoactive component of the radiation sensitive system to produce apatterned image in the resist coating layer. Suitable exposure energiestypically range from about 1 to 300 mJ/cm². An I-line (365 nm) exposurewavelength often preferably will be used for the photoresists of theinvention. Other suitable exposure include sub-300 nm such as 248 nm, orlonger wavelengths such as G-line (435 nm). Suitable post-exposure baketemperatures are from about 50° C. or greater, more specifically fromabout 50 to 140° C. For an acid-hardening negative-acting resist, apost-development bake may be employed if desired at temperatures of fromabout 100 to 150° C. for several minutes or longer to further cure therelief image formed upon development. After development and anypost-development cure, the substrate surface bared by development maythen be selectively processed, for example chemically etching or platingsubstrate areas bared of photoresist in accordance with procedures knownin the art. Suitable etchants include a hydrofluoric acid etchingsolution and a plasma gas etch such as an oxygen plasma etch.

[0097] All documents mentioned herein are incorporated herein byreference. The following non-limiting example is illustrative of theinvention.

EXAMPLE 1

[0098] Photoresist compositions of the invention were preparedcontaining PAGs of 1) diphenyliodonium9,10-dimethoxyanthracene-2-sulfonate (referred to below as “PAG 1”); 2)di(t-butylphenyl)iodonium 9,10-dimethoxyanthracene-2-sulfonate (referredto below as “PAG 2”); and 3) tri(t-butylphenyl)iodonium9,10-dimethoxyanthracene-2-sulfonate (referred to below as “PAG 3”).

[0099] More specifically, three positive-acting photoresist compositionswere prepared, referred to as Resists 1-3 respectively. Each of thephotoresists contained a resin mixture of 1) a partially hydrogenatedpolyvinylphenol polymer that had a portion of hydroxyl units masked withethoxyethyl groups, 2) a terpolymer of hydroxystyrene, styrene andt-butylacrylate groups. Resist 1 contained a PAG mixture of 1) PAG 1 and2) di(t-butylphenyl)iodonium camphorsulfonate. Resist 2 contained a PAGmixture of 1) PAG 2 and 2) di(t-butylphenyl)iodonium camphorsulfonate.Resist 3 contained a PAG mixture of 1) PAG 3 and 2)di(t-butylphenyl)iodonium camphorsulfonate. In each of the PAGs blendsof Resists 1-3, the anthracene acid PAG was present 4 parts by weight to1 part by weight of the camphorsulfonate PAG. The resin mixtureconstituted 93.25 weight percent of total solids (all components exceptsolvent) of each of Resists 1-3; the PAG blend constituted 6.0 weightpercent of total solids of each of Resists 1-3. Resists 1-3 were eachformulated at 6.3 weight percent solids in a solvent mixture of ethyllactate and propylene glycol methyl ether.

[0100] Each of Resists 1-3 were spin coated onto silicon wafers as wellas over silicon wafers with a cross-linked antireflective coating layer.Resist s were applied at a coating layer thickness of approximately 7650angstroms, and the coated substrates were soft-baked on a vacuumhotplate at 90° C. for approximately 60 seconds. The resist layers werethen exposed to patterned radiation of 365 nm (ASM stepper NA=0.6,σ=0.75). The exposed resist layers were then baked at 110° C. forapproximately 60 seconds and developed with 0.26N tetramethylammoniumhydroxide aqueous solution. 0.3 μm lines and spaces were resolved forResists 1 and 2, and inferior results were obtained for Resist 3.Accordingly, iodonium-based PAGs of the invention may be preferred oversulfonium-based PAGs.

[0101] The foregoing description of the invention is merely illustrativethereof, and it is understood that variations and modifications can beeffected without departing from the spirit or scope of the invention asset forth in the following claims.

What is claimed is:
 1. A photoresist composition comprising: a resinbinder and a photoacid generator compound in an amount sufficient topermit development of an exposed coating layer of the composition, thephotoacid generator generating an alkoxy anthracene sulfonate acid uponexposure to activating radiation, and selected from the group consistingof diaryliodonium salts, diphenyliodonium salts, dinaphthyliodoniumsalts, N-oxyimidosulfonates, N-oxyiminosulfonate, phenolic sulfonates,benzylic sulfonates, disulfones, diazosulfones, triarylsulfonium salts,aryl(dialkyl)sulfonium salts, phenacylsulfonium salts,naphthylacylsulfonium salts, or acenaphtylacylsulfonium salts, all ofwhich may be optionally substituted.
 2. The photoresist composition ofclaim 1 wherein the photo acid generator provides a9,10-dialkoxyanthracene-2-sulfonic acid upon exposure to activatingradiation.
 3. The photoresist composition of claim 1 wherein the photoacid generator provides an anthracene disulfonic acid upon exposure toactivating radiation.
 4. The photoresist composition of claim 1 whereinthe photoacid generator provides an anthracene acid that has bothsulfonic acid and alkoxy moieties upon exposure to activating radiation.5. The photoresist composition of claims 1 or 2 wherein the photoacidgenerator compound is a compound of any one of Formulae I, II, III, IV,V, VI, VII, VII, IX, X, XI, XIA, XIB, XIIA and XIIB as those formulaeare defined above.
 6. The photoresist composition of claims 1 or 3wherein the photoacid generator compound is a compound of any one ofFormulae I′, II′, III′, IV′, V′, VI′, VII′, VII′, IX′, X′, XI′, XIA′,XIB′, XIIA′ and XIIB′ as those formulae are defined above.
 7. Thephotoresist composition of claims 1 or 4 wherein the photoacid generatorcompound is a compound of any one of Formulae I″, II″, III″, IV″, V″,VI″, VII″, VII″, IX″, X″, XI″, XIA″, XIB″, XIIA″ and XIIB″ as thoseformulae are defined above.
 8. The photoresist composition of any one ofclaims 1-7 wherein the composition is a positive-acting photoresist. 9.The photoresist composition of any one of claims 1-7 wherein thecomposition is a chemically amplified positive-acting photoresist. 10.The photoresist composition of any one of claims 1-7 wherein thecomposition is a negative-acting photoresist.
 11. The photoresistcomposition of any one of claims 1-7 wherein the composition is achemically-amplified negative-acting photoresist.
 12. A method forforming a photoresist relief image on a substrate comprising: (a)applying a coating layer of a photoresist composition of any one ofclaims 1 through 11 on a substrate; and (b) exposing the photoresistcoating layer to patterned activating radiation and developing theexposed photoresist layer to provide a relief image.
 13. The method ofclaim 12 wherein the photoresist coating layer is exposed to radiationhaving a wavelength of about 365 nm.
 14. The method of claim 12 whereinthe photoresist coating layer is exposed to radiation having awavelength of less than about 300 nm.
 15. The method of claim 12 whereinthe photoresist coating layer is exposed to radiation having awavelength of about 248 nm.
 16. The method of claim 12 wherein thephotoresist coating layer is exposed to radiation having a wavelength ofabout 435 nm.
 17. An article of manufacture having on at least onesurface a coating layer of the photoresist composition of any one ofclaims 1-11.
 18. An article of manufacture comprising a microelectronicwafer that has on at least one surface a coating layer of a photoresistof any one of claims 1-11.
 19. An article of manufacture comprising aprinted circuit board substrate that has on at least one surface acoating layer of a photoresist of any one of claims 1-11.
 20. Thearticle of claim 19 wherein the printed circuit board substrate is acopper clad laminate.
 21. A photoacid generator compound that cangenerate an anthracene sulfonate acid upon exposure to activatingradiation, the photoacid generator compound generating an alkoxyanthracene sulfonate acid upon exposure to activating radiation, andselected from the group consisting of diaryliodonium salts,diphenyliodonium salts, dinaphthyliodonium salts, N-oxyimidosulfonates,N-oxyiminosulfonate, phenolic sulfonates, benzylic sulfonates,disulfones, diazosulfones, triarylsulfonium salts,aryl(dialkyl)sulfonium salts, phenacylsulfonium salts,naphthylacylsulfonium salts, or acenaphtylacylsulfonium salts, all ofwhich may be optionally substituted.
 22. The photoacid generator ofclaim 21 wherein the photoacid generator provides a9,10-dialkoxyanthracene-2-sulfonic acid upon exposure to activatingradiation.
 23. The photoacid generator of claim 21 wherein the photoacidgenerator provides an anthracene disulfonic acid upon exposure toactivating radiation.
 24. The photoacid generator of claim 21 whereinthe photoacid generator provides an anthracene acid that has bothsulfonic acid and alkoxy moieties upon exposure to activating radiation.25. The photoacid generator of claim 21 or 22 wherein the photoacidgenerator compound is a compound of any one of Formulae I, II, III, IV,V, VI, VII, VII, IX, X, XI, XIA, XIB, XIIA and XIIB as those formulaeare defined above.
 26. The photoacid generator of claim 21 or 23 whereinthe photoacid generator compound is a compound of any one of FormulaeI′, II′, III′, IV′, V′, VI′, VII′, VII′, IX′, X′, XI′, XIA′, XIB′, XIIA′and XIIB′ as those formulae are defined above.
 27. The photoacidgenerator of claim 21 or 24 wherein the photoacid generator compound isa compound of any one of Formulae I″, II″, III″, IV″, V″, VI″, VII″,VII″, IX″, X″, XI″, XIA″, XIB″, XIIA″ and XIIB″ as those formulae aredefined above.